Show current output device in toolbar

[aberonni]

This is a potentially easier-to-implement feature request with a similar need to #3. The need is for the user to understand which is the current output device. It could be solved by adding a label next to the icon with the name of the current output device.

PS thanks for the great free app!!

[elliottmangham]

I agree, adding a little dot or icon next to the active device would be so helpful.

Thank you @j-f1!